1. Field of the Invention
The present invention relates to the technical field of agricultural machinery and more specifically to the field of accessories used for hitching an agricultural machine to a tractor.
The present invention relates to an adapter device which allows the drawbar of an agricultural machine to be connected optimally to a hitching bar of a tractor. An adapter device of this kind is most particularly applicable in the field of trailed agricultural machines.
2. Discussion of the Background
The production of an adapter device for a hitching bar of agricultural machines comprising:
an adapter bar equipped with a hitching pin near one of its ends, said hitching pin extending substantially vertically when the adapter device is mounted on the hitching bar, and a connecting pin intended to pass through an opening made in said hitching bar, and PA1 means of allowing the mechanical play between the hitching bar and the adapter bar to be reduced or cancelled, is known. PA1 an adapter bar equipped with a hitching pin near one of its ends, said hitching pin extending substantially vertically when the adapter device is mounted on the hitching bar, and a connecting pin intended to pass through an opening made in said hitching bar, and PA1 means of allowing the mechanical play between the hitching bar and the adapter bar to be reduced or cancelled, PA1 wherein said means for reducing or cancelling the mechanical play between the hitching bar and the adapter bar comprise:
Such devices make it possible to optimize the distance between the tractor and the agricultural machine when the latter is driven by the power take-off of said tractor. The power take-off is generally connected to the agricultural machine via a cardan shaft, which consequently limits the inclination between the tractor and the hitching drawbar when said machine is being driven.
Optimizing the distance between the agricultural machine and the tractor power take-off therefore makes it possible to obtain inclinations of the transmission shaft ranging to as much as 45.degree. at a homokinetic joint. Furthermore, when the telescopic transmission shaft adopts its maximum extension, that is to say when the agricultural machine and the tractor are moving along in a straight line, it is essential that the telescopic parts overlap over a minimum distance.
Furthermore, the transmission shaft ends in a cardan joint at each end, thereby reducing the length available for the maximum overlap when the inclination of said transmission shaft is 45.degree. with respect to the direction of traction. All of these conditions impose a minimum length of the hitching bar, that can be achieved using the adapter device. The fact that the hitching bars which are delivered with the tractors are of a standardized length is therefore no longer an impediment to hitching certain types of machine.
The known device consists of an additional hitching bar which, at one of its ends, has a portion in the form of a rectangular tube in which the hitching bar of the tractor can engage. The rectangular tube portion therefore has openings which lie opposite an opening made in the hitching bar so that a connecting pin can be passed through these openings. This pin also passes through a set of shims housed inside the rectangular tube and intended to reduce the vertical mechanical play of the hitching bar in said rectangular tube. A clamping screw, mounted on a side wall, is designed to take up the lateral play of the hitching bar.
Such adapter devices have the drawback of not sufficiently taking up the mechanical play there is between the adapter bar and the hitching bar. Furthermore, the loadings are not transmitted uniformly to the hitching bar and therefore increase wear and the risk of damage.